Compact walk-around rebreathing device



Sept. 28, 1965 R. G. BARTLETT, JR 3,203,449

COMPACT WALK-AROUND REBREATHING DEVICE 5 Sheets-Sheet 1 Filed May 7, 1964 INVENTOR Roscoe 6. Barfletdn ||I l vi /A//% g n THU :2: @EE /W J; 3 I, W a0 o 4 1 p 28, 1965 R. s. BARTL-ETT, JR 3,208,449

COMPACT WALK-AROUND REBREATHING DEVICE Filed May '7, 1964 5 Sheets-Sheet 2 INVENTOR p 28} 1.965 R. G. BARTLETT, JR 3,208,449

COMPACT WALK-AROUND REBREATHING DEVICE Filed May '7. 1964 5 Sheets-Sheet 3 4 H//// I I l '5 lg;

. INVENTOR Sept. 28, 1965 R. G. BARTLETT, JR 3,208,449

COMPACT WALK-AROUND REBREATHING DEVICE Filed May '7, 1964 5 Sheets-Sheet 4 INVENTOR 82 Rosaoe G Bariiefl; J

Sept. 28, 1965, R. G. BARTLETT, JR 3,208,449

COMPACT WALK-AROUND REBREATHING DEVICE Filed May 7, 1964 5 Sheets-Sheet 5 INVENTOR ROSCO G EQIZZQZZZ J57 BY I ATTORNEY United States Patent 3,208,449 COMPACT WALK-AROUND REBREATHING DEVICE Roscoe G. Bartlett, Jr., Lime Kiln, Md. (8621 Georgia Ave., Silver Spring, Md.) Filed May 7, 1964, Ser. No. 365,846 14 Claims. (Cl. 128-29) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This application is a continuation-in-part of application Serial Number 166,005 now abandoned.

The present invention relates generally to respiratory apparatus and, more particularly, to a compact, selfcontained breathing device having an air regeneration feature for minimizing the amount of oxygen that must be supplied from an external storage element, as well as being useful in any contaminated atmosphere.

Self-contained breathing apparatus for use by individuals exposed to contaminated or rarefied atmospheres where insufficient oxygen is present for satisfying the ordinary demands of their respiratory systems, are known in the prior art. In one type of apparatus, a purifying canister containing a chemical charge of a known composition regenerates the exhaled air by effectively absorbing the carbon dioxide present therein and liberating oxygen in the reaction. The amount of oxygen so generated is insufficient to satisfy the inhalation demands for any appreciable period, and an auxiliary supply of oxygen is incorporated into the equipment to augment this limited source.

In the so-called demand breather, the amount of oxygen drawn from the auxiliary supply is automatically established by the breathing requirements of the individual, in order to find its maximuim utilization, the demand type of breathing apparatus should be portable, relatively compact and as light as possible. Also, it should be capable of fulfilling a single demand for a relatively long period, or repeated routine use for short time intervals. Furthermore, the complete assembly should not be uncomfortable to wear, and should not restrict the movements of the individual wearing it.

It is a primary object of the present invention to provide a Walk-around, self-contained demand breather of the air-regenerative type. Characterized by its compactness, its lightness, and its favorable weight-to-lifetime ratio, these all being accomplished by having the amount of oxygen drawn from storage proportional to the breathing effort and by employing air regeneration to minimize the oxygen demand.

The mask system which is the subject matter of this invention has no bulky tanks andpermits the wearer to reuse his own breath. Exhaled breath passes through an absorbent material which takes out carbon dioxide and moisture. Fresh oxygen is added, and the mixture is rebreathed.

Some circumstances under which the breathing apparatus of the invention is used also produces emergency conditions which require rescue and/or resuscitation of victims of shock or asphyxiation.

It is therefore a further object of this invention to combine the breathing device with means for utilizing it as a mouth to mouth resuscitator as well as a device for rescuing a victim from a dangerous environment.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considerd in connection with the accompanying drawings wherein:

FIG. 1 illustrates one modification of the present invention wherein the rebreathing container takes the form of a flexible, deformable bag;

FIG. 2 shows in cross section part of an alternative modification wherein the above container consists of a bellows; and

FIG. 3 is a simplified showing of the construction of a demand valve capable of being used in both of the above modifications.

FIG. 4 illustrates the invention wherein the breathing device is used in a resuscitation apparatus.

FIG. 5 is a section of FIG. 4 showing design details.

FIG. 6 is a section taken on the line 6-6 of FIG. 5.

FIG. 7 is a view taken in the direction of the arrows on line 7-7 of FIG. 5.

FIG. 8 is a section taken on the line 88 of FIG. 5.

FIG. 9 is a section taken on the line 99 of FIG. 4.

FIG. 10 is a modification of the breathing device used in a resuscitation apparatus.

Briefly and in somewhat general terms, the objects enumerated above are realized, according to one embodiment of the invention, by coupling a breathing tube in the lower portion of a face mask directly to one end of an air purifying canister, the other end of the canister communicating with a flexible, rebreathing container. Wrapped about this container is a lightweight, helical tube which serves as the auxiliary oxygen storage member. After this tube is charged, oxygen flows therefrom via a pressure-reducing valve and a demand valve to the rebreathing container. The pressure-reducing valve is secured to one end of the tube, and the demand valve is housed within the lower portion of the air purifying canister below the chemical charge. The latter valve, as is well known, opens whenever the pressure within the rebreathing container drops below atmospheric pressure, a condition which occurs in response to, for example, a single, deep inhalation or the continued inhalation efforts of the wearer. Fresh oxygen is thus released intermittently into the system to complement or, perhaps, replace that otherwise available from the reaction of the exhaled air and the chemical charge in the air purifying canister. By utilizing a length of tubing which is wound intimately about the outside of the canister as the compressed oxygen storage element and by locating the reducing valve at one end of this tubing and the demand valve inside the canister, all of the various components are concentrated in the immediate vicinity of the face mask. This consolidation promotes quick attachment of the apparatus during emergency conditions and, at the same time, minimizes the possibility of any parts thereof getting entangled with other equipment worn by the individual.

Referring now to FIG. 1 of the drawings, a conventional face mask 1 is provided at a lower portion thereof with a breathing tube section 2 which fits over the reduced end 3 of a cylindrical air purifying canister 4. In the particular mask configuration selected for illustration, only the nose and mouth of the wearer are covered. It will be readily appreciated that if the apparatus is to be used in an atmosphere which is contaminated with irritants additional protection must be included for the eyes of the wearer. The breathing tube section 2, like the rest of the mask, is fashioned from a form retaining elastic material and, consequently, the fit between it and the reduced end 3 of the air canister is airtight. The fit between is also sufficiently tight to provide the entire support for the canister and the other components attached thereto, as the total weight of the device does not exceed two pounds.

The air purifying canister 4, as best shown in FIG. 2, contains in the upper portion thereof a chemical charge 5. This charge, the composition of which is well known in the art, reacts with the air exhaled by the individual wearing the mask to absorb the carbon dioxide and liberate oxygen in the exchange. A lower screen 6, having an air filter 7 resting thereon, and an upper snap-on screen 8, backed by a second filter 9, maintained the charge in place while permitting the relatively free passage of air therethrough. The lower end of canister 4, in the case of the modification of FIG. 1, has clamped thereto by means of a suitable band 10, a rebreathing reservoir 11 made of, for example, a thin, transparent plastic, such as polyethylene. In the alternative construction of FIG. 2, the rebreather container takes the form of a pleated, accordion-type, rubber bellows 12.

As mentioned in the introductory remarks, the auxiliary oxygen storage element consists of a length of helical tubing 13 wound intimately about the upper portion of canister 4. This tubing, may be held in place by the friction between the inner surfaces of its individual turns and the confronting outer surface of the canister, terminates at one end thereof in a charging valve 14, through which oxygen at a relatively high pressure is initially fed into the apparatus. Connected to the other end of the helical tubing is a pressure gauge 15 for indicating initially when the oxygen storage element is fully charged and, thereafter, the amount of oxygen available at any particular time in the system. Secured to this gauge by suitable connectors 16 is a pressure-reducing valve 17 controlled by an adjusting screw 18. Since this pressure reducing valve is of conventional design, both the details of its structure and its manner of operation need not be described. The function of valve 17 is to reduce the pressure of the oxygen to a level which will not damage the demand regulator, and also reduce the possibility of serious damage to the respiratory system of the wearer. Although pressure gauge 15 is shown with its meter face 19 in a vertical plane, it will be understood that this gauge may be turned and orientated so that it can be conveniently read by the wearer at all times. Referring once more to FIG. 2, the low pressure side of reducing valve 17, is coupled by a connector 20 to a conventional demand valve, generally represented by reference character 21, located in the lower portion 22 of canister 4. This valve, which will be described hereinafter, is supported by the connector 20 and has a lower compartment which is vented to the atmosphere through a length of tubing 23 which leads to a port 24 formed in a side wall portion of canister 4. The demand valve also has a second aperture 25 which opens an upper compartment of the valve directly to the interior of the canister 4.

The operation of a typical demand valve such as 21,

may be seen by referring to FIG. 3, which is a simplified drawing of this component. The valve consists essentially of an inclosed housing 26 divided by a flexible diaphragm 27 into upper and lower compartments 28 and 29. Pivotally mounted about a stub shaft 30 extending from a side wall of the upper compartment 28 is an arm 31 having a curved end 32 biased by spring 33 against the upper surface of diaphragm 27. The other end of the arm is relatively straight portion 34, overlies the open end of an oxygen admission line 35 which is an extension of the connector 20. The lower compartment 29 is vented to the atmosphere by means of tubing 23 connected between outlet 36 and aperture 22 cut in the lower sidewall portion of canister 4. The positioning of the parts as seen in FIG. 3 illustrates the standby condition that normally exists when the mask is not in use as both the upper and lower sides compartments are open to atmosphere. The tension of spring 31 is sufficient to keep end 34 of arm 31 in blocking engagement with the oxygen admission line 35 to prevent the flow of oxygen into the apparatus at this time.

The operation of the device is as follows: when the wearer first pust on the mask, equal pressures exist on opposite sides of diaphragm 27 for the reason mentioned above, and arm 31 prevents the release of oxygen into the rebreathing bag. This is a temporary condition which .4 persists until the inspiratory effort of the wearer reduces the pressure in compartment 28. When this occurs the pressure in the upper compartment 28 will fall below that of the atmosphere, either because of the continued inhalation etfort or a single deep inhalation. The rebreather bag will then collapse and there will be a responsive upward displacement of diaphragm 27, which pivots arms 31 in a clockwise direction to open the oxygen admission line 35. Oxygen now enters the internal part of the apparatus, inflates rebreathing container and augments that being generated by the chemical charge. This flow continues until the pressure in upper compartment 28 is restored to approximately the atmospheric level. During this buildup, diaphragm 27 moves gradually back to its original horizontal position, as shown in FIG. 3, and when equal pressures once more exist on both sides of the diaphragm, arm 31 is again effective to block the further admission of oxygen. The above sequence, it will be appreciated, is of a continuous and cyclical nature and is automatically repeated according to the breathing demands of the wearer.

It will be appreciated from what has been described that the rebreathing apparatus operates on a closed cycle. That is, exhaled air passes down through tube section 2, chemical charge 5 and into the rebreathing container 11 or 12 and, in the following inhalation period, the air, with the carbon dioxide removed and with fresh oxygen added from the purifier and/ or the oxygen source, travels the reverse route back into the respiratory system of the individual wearing the face mask. Because of the twoway flow of air through the air purifying canister, there is an extension in the reaction time during which the chemical charge can purify the exhaled air. Thus, the efiiciency of this phase of the equipment is increased, and the size of the canister can be reduced for any given application. From an examination of FIG. 1, it will be seen that the complete apparatus may be quickly put in use for the individual need only slip on the face mask without making any preliminary external connections or adjustments, and his oxygen requirements will be automatically satisfied as soon as they become significant.

Since the oxygen storage device takes the form of tubing from directly above the purifying canister 4 and since this tubing and the controls cooperating therewith go directly into the rebreather, there is little possibility of the oxygen flow being interrupted by any accidental break in the supply line. Furthermore, the concentration and consolidation of the oxygen storage element and the control devices therefor in the immediate vicinity of the face mask permits the wearer of the apparatus to perform his usual movements without restriction and without the possibility of the apparatus getting entangled with other equipment worn by him.

For the most efficient operation of the rebreathing apparatus hereinbefore disclosed, the size of the chemical charge in the canister should be matched to the oxygen available in the storage element. In actual practice, it has been found that the carbon dioxide absorber preferably should last somewhat longer than the oxygen supply. To replace the charge, of course, it is only necessary to break the coupling between breathing tube section 2 and the top of the canister and then remove the upper screen and filter.

As indicated hereinbefore, the mask of the present invention serves the dual purpose of providing a seal for the face and support for the rebreather canister and the oxygen reservoir mounted thereabout. In the illustration of FIG. 1, the canister is shown as having an increased diameter where it extends beyond the mask. For most efficient operation, however, the diameter of the canister should be uniform, conforming to the size of the opening in the mask. Hence the rebreathing canister may take the form of a simple, cylindrical container. It would also be mentioned that in the apparatus of FIGS. 1 and 2 there are no valves or other air control devices in the mask itself. Consequently, there are no noise sources to interfere with the operation of communication equipment Worn by the individual.-

Some of the advantages of utilizing a thin-walled, helical tube as the oxygen container are as follows: -First of all, with this design, the storage element can be of lightweight construction and still possess suflicient capacity to satisfy the requirements of the wearer for perhaps an hour or so'when charged to approximately 2,000 lbs/sq. in. Although magnesium tubing offers the best solution as far as weight considerations go, the cost and the fire hazard created by utilizing this material more than offset this advantage. On balance, aluminum tubing has been found to provide the most satisfactory solution. In one practical embodiment of the present invention, aluminum tubing having a 0.035-inch wall thickness and a one-half inch outside diameter was used. The helical construction also results in the best distribution of weight and bulk for comfort and versatility in use. And finally, if ruptured, the aluminum tubing does not tend to explode but, rather, the material tears, thus allowing the impounded gas to escape rapidly .without producing a shrapnel-like discharge. Since the oxygen container is mounted close to the face of the wearer, this last-mentioned characteristic constitutes an important safety feature of the present invention.

In selecting a carbon dioxide absorber for use in the apparatus hereinbefore described, there are several obvious factors which should be considered. One is that since the absorption of carbon dioxide is largely surface dependent, the air should be exposed to as large a surface as possible. This means, of course, that the absorber should be in the form of small particles. However, when the particle size decreases, there is an accompanying decrease in the interstices between particles and increase in the resistance to gas movement therethrough. A com promise must, therefore, be made between the employment of dustlike particles .which would expose the contaminated air to the largest possible surface and very large particles which would produce minimum resistance to air movement.

One of the best carbon dioxide absorbers is lithium hydroxide. However, the very irritating effects of dust from this absorber complicate the design of the screening apparatus employed to prevent this dust from entering the respiratory system of the wearer. It would also be mentioned that some of the absorbers generate a great deal of heat and, in warm environments, this characteristic may make the wearer of a device employing these substances somewhat uncomfortable. Another factor that influences the selection of the carbon dioxide absorbing substance is the conformation of its particles. Thus, for example, if large, smooth pellets are used, only the exterior layer of these particles participates in the reaction. Granular, irregular shapes, on the other hand, afford larger surfaces for absorption and, additionally, maintain sufficiently large interstices to keep the resistance to air movement therethrough low.

As an alternative to the simple carbon dioxide absorbers referred to hereinbefore, a chemical oxygen source which is a C absorber, such as potassium or sodium superoxide, may be used. These chemicals not only absorb carbon dioxide but also generate oxygen. Thus, with chemicals of this nature, less compressed oxygen would be required in the system. However, it would be noted that there are some risks attending the employment of these chemicals, such as the danger of the canister being crushed and the wearer directly exposed to these caustic materials and the possibility under certain circumstances of the oxygenation outrunning the oxygen use rate. If this last condition occurs, the rebreathing reservoir fills up and a dumping valve would have to be available to void this excess gas.

The rebreathing accumulator, as shown in the modifications of FIGS. 1 and 2, can take the form of either a simple, thin-walled, polyethylene bag or a pleated, accordion-type, rubber bellows. The latter design has several advantages. The volume displacement of the device when in use can be reduced by constructing the bellows so that it normally operates from a collapsed rather than a full position. Also, the use of rubber in the construction of the reservoir results in a more durable device. If a thin-walled rubber bellow's is used, a subsequent expiration after a deep inspiration would simply fill the belloWs to its capacity and then blow it up like a balloon. This would accommodate the larger expiration with only a noticeable increase in pressure at the end of expiration. Such an increase in pressure would warn the deep breather of potential hyper-ventilation if he were to continue his deep breathing.

It would also be pointed out that the incorporation of the pressure-reducing valve in the oxygen delivery line permits a simple and lightweight demand valve to be used in the system. In other words, if the demand valve had to withstand the high pressure at which the oxygen is stored, its weight and bulk would have to be considerably increased. It would also be mentioned that the demand valve preferably should be supplied with oxygen in the range from 50 to lbs./ sq. in.

For use as a resuscitator the breathing apparatus described above is modified to provide a connection to a conduit means which is attached to a face mask worn by the person to be resuscitated. The arrangement is such that the rescuer wearing the breathing apparatus can exhale to increase the pressure of the air in the victims mask to thereby force air into the lungs, and during the rescuers inhalation phase, the elastic recoil of the chest lining complex of the victim produces the victims exhalation.

In one form of resuscitator only one of the masks is supplied with an air purifier and oxygen supply. The conduit means of this form of the invention is arranged to allow air to flow in one direction only from the air purifier to the victims mask and back to the air purifier.

In a second form of the invention both masks are supplied with an air purifier and oxygen supply. The accumulators in this form provide a flexible diaphragm such that an increase in pressure in one of the masks produces an increase of pressure in the other mask to force air into the lungs of the victim.

Referring now to FIG. 4 of the drawings a face mask 40 is connected to a face mask 42 by means of a flexible conduit 44. Both masks are supplied with straps 43 for securing the masks over the mouth and nose of the wearer and both masks are supplied with a protective seal 45 to protect the skin of the wearer from chafing by the material of the mask and to seal the edges of the mask to the face. The details for connecting the conduit to mask 40 are shown in FIGS. 5, 6 and the details for connecting the conduit to mask 42 are shown in FIG. 9.

A flanged sleeve 46 is secured to the body portion of the face mask by means of a bayonet joint and elastic seal ring 48 and forms a support by the mask for the apparatus to be described below. A flexible sleeve 50 is secured to the sleeve 46 by a clamp ring 52 and is secured to a neck 54 of a flanged member 56 by a clamp ring 58. A chamber 60 is secured to the flange member by screws 62 and serves as a separating chamber to keep separated the air which is channeled to mask 42 from the air which is being returned from said mask.

The chamber 60 is provided with a separating wall 64 which divides the chamber into a valve chamber 66 and a return chamber 68. The valve chamber is provided with a valve 70 which is moved to the dotted line position to allow air to flow into the chamber from the air purifier upon reduction of pressure in the chamber such as on inhalation by the wearer of mask 40, and prevents the flow of air from the chamber into the air purifier by moving to the solid line position. A conduit 72 is secured 7 to the wall 64 to connect to conduit 44 to conduct purified air to mask 42.

Chamber 68 is merely part of the conduit means to receive the return air from mask 42 and conduct it to the purifier. This chamber is vented to the air purifier by opening 74.

A flanged sleeve 76 is secured in an opening in the chamber 60 by means of a bayonet joint and elastic seal ring 78. The bayonet joint comprises lugs 80 fixed to the sleeve and slots 82 in the wall of the chamber. The sleeve is provided with a central conduit portion 84 and a concentric conduit portion 86 for connection to the corresponding portions of conduit 44. The conduit portions are held spaced by walls 88 which extend only a short distance along the axis of the sleeve in order to allow the inner tube 90 of conduit 44 to be mounted about the conduit portion 84. The outer tube 92 of conduit 44 is secured to conduit portion 86 of sleeve 76 by a clamp ring 94. The tubes 90 and 92 are shown held in concentric positions by wall portions 93.

The assembly of conduit 44 and sleeve 76 can be quickly disconnected from the breathing apparatus by means of the bayonet joint 80, 82 by merely a slight twist and a separating movement by one hand only. When the assembly is removed a safety flap 96 biased by a spring 98 quickly closes the opening and bears against seal ring 78 to seal the interior of the apparatus from the exterior atmosphere. The device returns to the status of a breathing apparatus wherein the air is channeled to flow through the air purifier on one direction only. That is, on exhaling the air leaves the end of the tube 72 and flows through chamber 68 to the chemical charge. In inhaling valve 70 is lifed to admit purified air to the mask.

The conduit 44 is connected to mask 42 by a flanged sleeve 100 secured to the mask by a bayonet joint similar to the joints previously described and an elastic seal ring 102. This sleeve is formed with a central conduit portion 104 and a concentric conduit portion 106. The inner tube 90 is fitted over the portion 104 and the outer tube is secured to conduit portion 106 by a clamp ring 108. A value 110 is mounted on the sleeve 100 to allow air to pass into the mask from tube 90 by moving to the dotted line position and by moving to the solid line position serves to prevent air from passing in the reverse direction.

An air purifying canister 112 is secured to chamber 60 by threaded fasteners such as screws 114 and has frictionally mounted thereon a length of helical tubing 116 which serves as a reservoir for oxygen. One end of the tubing has secured thereto a charging value 117 (tight) whereby to charge the reservoir with oxygen under high pressure, and a pressure reducing valve 120 is mounted on the other end whereby to reduce the pressure of the oxygen before it is fed to demand valve 21 within the canister as shown in FIG. 2 for example. A pressure gauge 119 indicates the pressure existing in the reservoir at all times and thus serves as a warning that the oxygen supply may be too low for safety. A tubular container 118 is mounted in the canister and is filled with a chemical charge 120 such as charge 5. The charge is retained in the container by a filter 122 and screen 124 at both ends of the container and which are similar to filters 7 and 9 and screen 6 and 8 shown in FIG. 2.

A rebreathing reservoir or accumulator 126 similar to 11 or '12 of FIGS. 1 and 2 is secured to canister 112.

Both masks are supplied with an anti-suffocation valve 128 which can be manually operated to vent the interior of the mask to the outside atmosphere when the oxygen supply is gone or not needed. The valve is shown as comprising a head 130 biased against a seal ring 132 by a spring 134. A manual valve operator 136 is provided with a central bore 138 and lateral bores 140. Finger pressure on the operator 136 serves to vent the mask by means of bores 138, 140 and by slightly twisting the operator the valve is locked in the venting position. In

normal use the spring loads the valve so that a vacuum of three inches of water opens the valve to atmosphere.

In use the mask 40 is strapped to the rescuer and mask 42 is strapped to the victim by means of straps 43. The rescuer exhales to force purified air through tube in the direction of the arrows to the victims mask and inhales to draw purified air from the purifier and air from the victims mask through pipe 92 in the direction of the arrows. Valves 70 and prevent reverse flow of air and there is therefore a continuous flow of purified air to the victim. If the victim recovers sufiiciently conduit 44 can be quickly removed from both masks and a separate breathing apparatus with a supply of oxygen and an air purifier such as shown in FIG. 5 can be quickly attached to the victims mask. The emergency conditions under which the apparatus of this invention is used are many and varied and the apparatus can be used as a breathing device or resuscitator or both.

In FIG. 10 is shown a modification of resuscitator in which masks 40 and 42 are connected by flexible conduits 150, 152 to individual air purifiers and oxygen supplies similar to that shown in FIGS. 4 and 5 and to which the same numerals are used to designate corresponding parts. The adjacent ends of canisters 112 are modified to provide a bayonet joint or other quick connect and disconnect type of fastener whereby the canisters can be quickly connected and disconnected. In FIG. 10 rivets 154 are secured to the flange of one canister 112 by being expanded in openings therein and are slidably received in key hole openings in the other flange. Members 126 are bonded to the flanges and provided with openings to receive the rivets.

In use, mask 40 (or 42) is strapped to the rescuer and mask 42 (or 40) is strapped to the victim by means of straps 43. The rescuer exhales to thereby increase the pressure in the canister of his mask and force members 126 into the canister of the victims mask to thereby increase the pressure in the victims mask to force air into the lungs. On inhaling by the rescuer, the elastic recoil of the chest lining complex of victim forces air from the lungs of the victim and thus helps the rescuer to inhale to help conserve his lung power as well as applying the resuscitation forces to the victim. If the victim recovers sufficiently the canisters can be quickly separated to allow maximum mobility for rescuer and rescued. Of course the rescuer can quickly attach his apparatus to the victims and commence resuscitation efforts with no waste of time.

In order to avoid excess pressure each canister is supplied with a safety valve 156 to vent the canister to atmosphere.

I claim:

1. A compact, walk-around rebreathing device comprising, in combination, a face mask, said face mask including a rebreathing tube one end of which communicates with the inside of said face mask and the other end of which is open, a cylindrical member housing a carbon dioxide absorbing substance, one end of said member being coupled to the opened end of said rebreathing tube, and an expandable rebreathing accumulator coupled to the other end of said member, said face mask, cylindrical member and accumulator forming when said face mask is in place a closed breathing system in which air dispelled during the exhalation part of the breathing cycle of the individual wearing said face mask passes via said rebreathing tube, said carbon dioxide absorption substance into said rebreathing accumulator and thereafter retraces this path during the inhalation part of the breathing cycle of said individual, a helical oxygen storage device positioned about said cylindrical member and means responsive to the creation within said closed breathing system by the inhalation efforts of said individual of a pressure level less than that of the outside atmosphere for releasing oxygen from said oxygen storage device into 9 said closed breathing system for replenishing the oxygen content of said air.

2. A walk-around rebreathing device for sustaining an individual in a contaminated atmosphere comprising, in combination, a face mask, said mask being made of a flexible material and having a tube one end of which communicates with the inner part of said face mask and the other end of which is open, a cylindrical container, one end of said container fitting intimately within the open end of said breathing tube, an expandable rebreathing accumulator connected to the other end of said cylindrical container, said face mask, said container and said accumulator forming a closed breathing system when said face mask is in place, a porous carbon dioxide absorbing substance retained with said container such that a twoway air flow can take place through said substance in response to the inhalation and exhalation elforts of the individual wearing said face mask, a length of tubing wrapped about said cylindrical container, means for charging said tubing with compressed oxygen and means automatically controlled by the breathing demands of the individual wearing said mask for releasing oxygen from said tubing into said closed breathing system.

3. A compact, Walk-around rebreathing device for sustaining an individual in a contaminated atmosphere, the combination of a face mask, said mask including as an integral component thereof a breathing tube which communicates at once end with the inside of said face mask and which has its other end open, a cylindrical sleeve, one end of said sleeve fitting within the open end of said breathing tube, an expandable air storage device connected to the other end of said sleeve, chemical means positioned within a portion of said cylindrical container for absorbing carbon dioxide present in the exhaled air dispelled by the individual Wearing said face mask, a length of tubing wrapped about the outside of said sleeve, means for storing compressed oxygen within said tubing and means responsive to the breathing demands of the individual wearing said face mask for releasing oxygen from said tubing into an unoccupied portion of said sleeve thereby to sustain the respiratory system of the individual wearing said face mask.

4. A lightweight, compact, rebreathing device for sustaining an individual exposed to a contaminated atmosphere, in combination, a flexible face mask, said face mask covering at least the nose and mouth of the wearer and including a rebreathing tube which communicates with the inside of said face mask and terminates in an open end, a canister, a carbon dioxide absorbing substance retained in the upper portion of said canister, one end of said canister being connected to the open end of said breathing tube in an airtight manner, an expandable rebreathing accumulator connected to the other end of said canister, a lightweight tubing wrapped about the outside of said canister and supported therefrom, said tubing containing oxygen under pressure, means responsive to the breathing demands of the individual Wearing said mask for releasing oxygen stored in said helical tubing into said canister below the carbon dioxide absorbing substance.

5. For use with a portable rebreathing device of the type including a face mask, a canister containing a carbon dioxide absorbing substance coupled thereto and a rebreathing accumulator coupled to said canister, the combination of a length of helical tubing wound about said canister, said tubing being charged with compressed oxygen, a pressure reducing means connected to one end of said tubing, a demand valve positioned within an otherwise unoccupied portion of said canister and coupled to the low pressure side of said pressure reducing means, said demand valve responding to less than ambient atmospheric pressures developed within said canister by the continued inhalation effort of the individual wearing said mask and releasing oxygen from said tubing into said canister for assisting the breathing action of said individual.

6. A compact, lightweight, walk-around rebreathing device comprising, in combination, a face mask made of flexible material, said face mask being adapted to enclose at least the nose and mouth of the individual wearing it and including as an integral component thereof a rebreathing tube, one end of which communicates with the inside of said face mask and the other end of which is open, a canister containing in the upper portion thereof a carbon dioxide absorbing substance, means for establishing an airtight connection between one end of said canister and the open end of said breathing tube, a flexible rebreathing accumulator connected to the other end of said canister, said face mask, canister and accumulator forming a closed breathing system whereby air exhaled by the individual wearing said face mask passes via said breathing tube and through said carbon dioxide absorbing substance into said accumulator during his exhalation efforts and retraces this path during his inhalation eiforts, a tubing wrapped about the outside of said canister, said tubing containing oxygen stored under pressure, a demand valve positioned within the lower portion of said canister and connected to said tubing, said demand valve being controlled by the breathing demands of the individual wearing said face mask and releasing oxygen from said tubing into the closed breathing system to satisfy the respiratory system of the individual wearing the face mask.

7. A compact rebreathing device comprising a face mask, a canister containing a carbon dioxide absorbing chemical and a deformable rebreathing accumulator, said face mask, canister and container being interconnected in a closed system whereby air dispelled by an individual wearing said face mask passes through said carbon dioxide absorbing substance and into said rebreathing accumulator and thence back through said carbon dioxide absorber and into said face mask when the individual inhales, a length of tubing wrapped about said canister, means for charging said tubing with compressed oxygen and means responsive to less than atmospheric pressure within said closed system for releasing oxygen from said tubing into the system to aid the respiratory action of the individual, said last-mentioned means including a pressure reducing valve and a demand valve.

8. A rebreathing device comprising in combination, a face mask, said mask including a rebreathing tube which has one end communicating with the inside of said face mask and the other end open, a canister containing in the upper portion thereof a carbon dioxide absorbing substance, one end of said canister fitting intimately within the opened end of said rebreathing tube, whereby an airtight connection is established therebetween of suflicient strength to support said canister from said face mask, an expandable rebreathing accumulator coupled to the lower end of said canister whereby air expelled by an individual wearing said face mask passes via said rebreathing tube and said carbon dioxide substance into said rebreather accumlator and back through said carbon dioxide adsorbing substance and said tube during the inhalation efforts of said individual, a length of tubing wrapped about said canister, a charging valve connected to one end of said tubing, a pressure reducing valve connected to the other end of said tubing, compressed oxygen stored within said tubing, a demand valve positioned within the lower portion of said canister, said demand valve having a first oxygen receiving chamber open to the canister, and a second cham ber open to the atmosphere, a tubular connector coupling the first chamber to the oxygen supply reducing valve, a control valve within the chamber for opening and closing the tubular connector, and means within said demand valve and responsive to ditferentials in pressure between said chambers for actuating said control valve.

9. A walk-around rebreather for use by an individual exposed to a contaminated atmosphere comprising, in combination, a face mask, said mask including a breathing tube which extends from a lower portion thereof, a sleeve, one end of said sleeve fitting into said breathing tube and forming an airtight seal therewith, a carbon dioxide absorber positioned within the upper portion of said sleeve, said absorber being retained in place by an upper and lower screen, a helical tube surrounding said sleeve and held in place by the friction therebetween, compressed oxygen stored within said helical tube, a pleated bellows secured to the lower end of said sleeve, and means responsive to the inhalation efforts of the individual wearing said face mask for releasing oxygen from said helical tubing into the lower portion of said sleeve at a rate established by the breathing demands of said individual.

10. A rebreathing device comprising, in combination,

a face mask, said face mask having an open breathing tube section in the lower portion thereof,

a canister having upper and lower open ends,

a carbon dioxide absorbing substance disposed and wholly carried in the canister adjacent the upper end thereof,

an expandable rebreathing accumulator coupled to and wholly carried by the lower end of the canister and closing the lower open end thereof,

a lightweight oxygen storage tube mounted around the exterior of the canister and wholly carried thereby,

said storage tube having a normally closed free end and an outlet end,

a charging valve carried at the free end of the storage tube thereby permitting said tube to be recharged in place on the canister,

differential pressure valve means disposed between the carbon dioxide absorber and the accumulator and within and wholly carried by the canister,

said differential pressure valve means being responsive to the difference in pressure in the canister and the ambient pressure of the atmosphere outside the canister, and,

an oxygen supply connection from the valve means to the outlet end of said storage tube whereby oxygen is permitted to flow from the storage tube into the canister by the operations of said differential pressure valve means,

said canister and the elements carried thereby providing a unitary structure and when the face mask is in place, a compact, portable, self-contained breathing system.

11. A device as defined in claim including:

a chamber disposed between the face mask and the top of the canister;

a partition wall dividing the chamber into a valve compartment and a return compartment; said valve compartment being open to the mask at its upper end, and open to the canister at its lower end;

a one way valve closing off the lower end of the valve compartment during exhalation and opening it during inhalation; said return compartment being closed at its upper end and open to the canister at its lower end;

a by pass conduit connecting said compartments;

said chamber having an outlet to atmosphere in the return compartment aligned with and of greater cross sectional area than the bypass conduit;

and a closure valve for said outlet.

12. A device as defined in claim 11 including;

a second mask;

a flexible conduit connected at one end to the mask;

an inner tube within the flexible conduit dividing the conduit into inner and outer passages;

and means at the other end of the flexible conduit for connecting it into said chamber outlet with the inner tube connected to the by pass conduit and for providing an inner passage from the valve compartment to the second mask, and an outer passage from the return compartment to the second mask;

and a second one way valve at the end of the inner tube at the second mask, positioned to open upon exhalation from the first mask and to close during exhalation from the second mask.

13. In combination with a portable self contained rebreathing apparatus of the type having a face mask and a container for carbon dioxide absorbent material therein, the improvement for utilizing the device for resuscitation comprising;

a chamber positioned between the face mask and the absorbent container;

a partition Wall in said chamber dividing it into a valve compartment connecting the face mask to the absorbent container and a return compartment opening into the absorbent container;

a one way valve in the valve compartment closing off the absorbent container during exhalation and opening it during inhalation;

a by pass conduit from the valve compartment to the return compartment; said chamber having an outlet to atmosphere aligned with and of greater cross sectional area than said by pass compartment;

and a second valve normally closing said outlet.

14. In a device as defined in claim 13, the addition of; a second mask; a conduit connecting one end of the conduit to the second mask; an inner tube within said conduit dividing said conduit into an inner and outer passage; and means receivable within the chamber outlet connecting the flexible tube outer passage to the return compartment and the inner passage to the by pass conduit and closing it off from the return compartment.

References Cited by the Examiner UNITED STATES PATENTS 2,269,500 1/42 Wildhack 128-142 2,453,475 11/48 Tobias 128-29 2,887,104 5/59 Sovinsky 128-29 3,044,654 7/62 Creighton 220-3 FOREIGN PATENTS 15,852 1897 Great Britain. 216,459 5/24 Great Britain. 901,357 7/62 Great Britain. 934,973 8/63 Great Britain.

RICHARD A. GAUDET, Primary Examiner. 

1. A COMPACT, WALK-AROUND REBREATHING DEVICE COMPRISING, IN COMBINATION, A FACE MASK, SAID FACE MASK INCLUDING A REBREATHING TUBE ONE END OF WHICH COMMUNICATES WITH THE INSIDE OF SAID FACE MASK AND THE OTHER END OF WHICH IS OPEN, A CYLINDRICAL MEMBER HOUSING A CARBON DIOXIDE ABSORBING SUBSTANCE, ONE END OF SAID MEMBER BEING COUPLED TO THE OPENED END OF SAID REBREATHING TUBE, AND AN EXPANDABLE REBREATHING ACCUMULATOR COUPLED TO THE OTHER END OF SAID MEMBER, SAID FACE MASK, CYLINDRICAL MEMBER AND ACCUMULATOR FORMING WHEN SAID FACE MASK IS IN PLACE A CLOSED BREATHING SYSTEM IN WHICH AIR DISPELLED DURING THE EXHALATION PART OF THE BREATHING CYCLE OF THE INDIVIDUAL WEARING SAID FACE MASK PASSES VIA SAID REBREATHING TUBE, SAID CARBON DIOXIDE ABSORPTION SUBSTANCE INTO SAID REBREATHING ACCUMULATOR AND THEREAFTER RETRACES THIS PATH DURING THE INHALATION PART OF THE BREATHING CYCLE OF SIAD INDIVIDUAL, A HELICAL OXYGEN STORAGE DEVICE POSITIONED ABOUT SAID CYLINDRICAL MEMBER AND MEANS RESPONSIVE TO THE CREATION WITHIN SAID CLOSED BREATHING SYSTEM BY THE INHALATION EFFORTS OF SAID INDIVIDUAL OF A PRESSURE LEVEL LESS THAN THAT OF THE OUTSIDE ATMOSPHERE FOR RELEASING OXYGEN FROM SAID OXYGEN STORAGE DEVICE INTO SAID CLOSED BREATHING SYSTEM FOR REPLENISHING THE OXYGEN CONTENT OF SAID AIR. 